Ethylene / propylene / non-conjugated diene terpolymer with reversible crosslink

Abstract

The present disclosure provides a composition. In an embodiment, a crosslinkable polymer composition is provided and includes an ethylene / propylene / non-conjugated polyene terpolymer, a free radical initiator, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS). The present disclosure also provides an article composed of the crosslinkable polymer composition. The article includes a crosslinked composition composed of the ethylene / propylene / non-conjugated polyene terpolymer, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS).

Description

ETHYLENE / PROPYLENE / NON-CONJUGATED DIENE TERPOLYMER WITH REVERSIBLE CROSSLINKBACKGROUND

[0001] Thermoset, cross-linked ethylene / propylene / non-conjugated polyene terpolymer elastomers are widely used in transportation and infrastructure applications such as automotive weather sealing, automotive under-the-hood hoses and belts, and roofing membranes. Most commonly, ethylene / propylene / non-conjugated polyene terpolymer is crosslinked via peroxides or sulfur. Other crosslinking chemistries such as phenolic and hydrosilylation are also practiced. In each of these cases, the crosslinks formed are substantially permanent-that is, no dissociation of the crosslinks occurs until an elevated temperature is reached at which the polymer backbone begins to degrade. Crosslinking ethylene / propylene / non-conjugated polyene terpolymer imparts improved thermo-mechanical properties, such as high-temperature compression set and creep resistance. However, crosslinked ethylene / propylene / non-conjugated polyene terpolymer compounds cannot be melt re-processed or recycled, generating waste that can only be landfilled or incinerated.

[0002] The art recognizes the need for a crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition that can be recycled and / or reprocessed. A need further exists for an ethylene / propylene / non-conjugated polyene terpolymer composition that can be reversibly crosslinked.SUMMARY

[0003] The present disclosure provides a composition. In an embodiment, a crosslinkable polymer composition is provided and includes an ethylene / propylene / non-conjugated polyene terpolymer, a free radical initiator, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS).

[0004] The present disclosure provides an article. In an embodiment, the article includes a crosslinked composition composed of the ethylene / propylene / non-conjugated polyene terpolymer, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS).

[0005] The present disclosure provides a process. In an embodiment, the process includes heating a first article to a reprocessing temperature. The first article is made from, or otherwise is composed of, a crosslinked composition. The crosslinked composition includes the ethylene / propylene / non-conjugated polyene terpolymer, and linkages having the Structure (2) (formed from 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate)).Structure 2The process includes forming, at the reprocessing temperature, the first article into a reprocessable ethylene / propylene / non-conjugated polyene terpolymer composition. The process includes shaping, at the reprocessing temperature, the re-processable ethylene / propylene / non- conjugated polyene terpolymer composition into a re-processed pre-form. The process includes cooling the re-processed pre-form to below the reprocessing temperature and forming a second article composed of a re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition composed of (i) the ethylene / propylene / non-conjugated polyene terpolymer (or EPDM) and (ii) the BiTEMPS methacrylate.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a photograph of comparative sample A (CS-A), after re-molding, FIG. 1 showing that CS-A is not reprocessable.

[0007] FIG. 2 is a photograph of CS-B after re-molding, FIG. 2 showing that CS-B is not reprocessable.

[0008] FIG. 3 is a photograph of CS-C after re-molding, FIG. 3 showing that CS-C is reprocessable.

[0009] FIG. 4 is a photograph of inventive example 2 (IE-2) after re-molding, FIG. 4 showing that IE-2 is reprocessable.

[0010] FIG. 5 is a photograph of CS-D after re-molding, FIG. 5 showing that CS-D is not reprocessable.

[0011] FIG. 6 is a photograph of IE-3 after re-molding, FIG. 6 showing that IE-3 is reprocessable.

[0012] FIG. 7 is a photograph of IE-4 after re-molding, FIG. 7 showing that IE-4 is reprocessable.DEFINITIONS

[0013] All references to the Periodic Table of the Elements herein shall refer to the Periodic Table of the Elements, published and copyrighted by CRC Press, Inc., 2003. Also, any references to a Group or Groups shall be to the Group or Groups reflected in this Periodic Table of the Elements using the IUPAC system for numbering groups. Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are based on weight. For purposes of United States patent practice, the contents of any patent, patent application, or publication referenced herein are hereby incorporated by reference in their entirety (or the equivalent US version thereof is so incorporated by reference).

[0014] The numerical ranges disclosed herein include all values from, and including, the lower value and the upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7) any subrange between any two explicit values is included (e.g., the range 1- 7 above includes subranges from 1 to 2; from 2 to 6; from 5 to 7; from 3 to 7; from 5 to 6; etc.).

[0015] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are based on weight, and all test methods are current as of the filing date of this disclosure.

[0016] The term "composition," as used herein, refers to a mixture of materials which comprise the composition, as well as reaction productsand decomposition products formed from the materials of the composition.

[0017] The terms "comprising," "including," "having," and their derivatives, are not intended to exclude the presence of any additional component, step or procedure, whether or not the same is specifically disclosed. In order to avoid any doubt, all compositions claimed through use of the term "comprising" may include any additional additive, adjuvant, or compound, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term, "consisting essentially of" excludes from the scope of any succeeding recitation any other component, stepor procedure, excepting those that are not essential to operability. The term "consisting of" excludes any component, step or procedure not specifically delineated or listed.

[0018] An "ethylene-based polymer" is a polymer that contains more than 50 mole percent polymerized ethylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylene-based polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Nonlimiting examples of ethylene-based polymer (polyethylene) include low density polyethylene (LDPE) and linear polyethylene. Nonlimiting examples of linear polyethylene include linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), multi-component ethylene-based copolymer (EPE), ethylene / a-olefin multi-block copolymers (also known as olefin block copolymer (OBC)), substantially linear, or linear, ethylene / a-olefin copolymers, plastomers / elastomers, and high density polyethylene (HDPE). Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such as Ziegler-Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, nonmetallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and / or homogeneous catalysts also may be used in either single reactor or dual reactor configurations.

[0019] The terms "interpolymer," and "copolymer," refer to a polymer prepared by the polymerization of at least two different types of monomers. These generic terms include both classical copolymers, i.e., polymers prepared from two different types of monomers, and polymers prepared from more than two different types of monomers, e.g., terpolymers, tetrapolymers, etc.

[0020] A "heteroatom" is an atom other than carbon or hydrogen. The heteroatom can be a non-carbon atom from Groups IV, V, VI and VII of the Periodic Table. Nonlimiting examples of heteroatoms include: F, N, O, P, B, S, and Si.

[0021] A "hydrocarbon" is a compound containing only hydrogen atoms and carbon atoms. A "hydrocarbonyl" (or "hydrocarbonyl group") is a hydrocarbon having a valence (typically univalent). A hydrocarbon can have a linear structure, a cyclic structure, or a branched structure.

[0022] An "olefin-based polymer," or "polyolefin," as used herein is a polymer that contains more than 50 mole percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. Nonlimiting examples of olefin-based polymer include ethylene-based polymer and propylene-based polymer.

[0023] A "polymer" is a compound prepared by polymerizing monomers, whether of the same or a different type, that in polymerized form provide the multiple and / or repeating "units" or "mer units" that make up a polymer. The generic term polymer thus embraces the term homopolymer, usually employed to refer to polymers prepared from only one type of monomer, and the term copolymer, usually employed to refer to polymers prepared from at least two types of monomers. It also embraces all forms of copolymer, e.g., random, block, etc. The terms "ethylene / a-olefin polymer" and "propylene / a-olefin polymer" are indicative of copolymer as described above prepared from polymerizing ethylene or propylene respectively and one or more additional, polymerizable a-olefin monomer. It is noted that although a polymer is often referred to as being "made of" one or more specified monomers, "based on" a specified monomer or monomer type, "containing" a specified monomer content, or the like, in this context the term "monomer" is understood to be referring to the polymerized remnant of the specified monomer and not to the unpolymerized species. In general, polymers herein are referred to as being based on "units" that are the polymerized form of a corresponding monomer.TEST METHODS

[0024] Compression set was measured using one specimen per sample according to ASTM D395 Method B and Type 1 sample dimension with 25% strain at 100 °C for 22 hours.

[0025] Density was measured in accordance with ASTM D792 with results reported in g / cc at 25°C.

[0026] Melt index (Ml or I2) (for ethylene-based polymers) was measured in accordance with ASTM D1238 (190 °C / 2.16 kg) with results reported in grams per 10 minutes (g / 10 min).

[0027] Mooney viscosity test: EPDM Rubber Mooney Viscosity was measured in a Mooney shearing disk viscometer in accordance with ASTM D1646. The instrument was an Alpha Technologies Mooney Viscometer 2000. The torque to turn the rotor at 2 rpm was measured by a torque transducer. The sample was preheated for 1 minute (min) after the platens were closed. The motor was then started and the torque was recorded for a period of 4 minutes (min). Results were reported as "ML (1+4) at 125°C" in Mooney Units (MU). The term "ML" indicates that a large rotor, "Mooney Large," was used in the viscosity test, where the large rotor is the standard size rotor. Mooney viscosity (MV) measures the resistance of polymer to flow at a relatively low shear rate and indicates the flowability of the polymer.

[0028] Rheology analysis using Rubber Process Analyzer (RPA). Rheology of the compositions was measured using a rotorless oscillating shear rheometer, Alpha Technologies RPA 2000 instrument, according to ASTM D6204, under the following test conditions and exceptions. The sample was placed between two pieces of Mylar film for analysis. Rheology was monitored during an initial timed test at 160 °C, 1.0 rad / s, 7% strain, for 60 min. Elastic torque, S', at the end of the 60 min crosslinking step was recorded. Immediately following the 60 min at 160 °C, a frequency sweep from 0.1 to 300 rad / s was conducted at 160 °C, 7% strain on the same sample, followed by a frequency sweep from 0.1 to 300 rad / s at 190 °C, 7% strain, and followed by a frequency sweep from 0.1 to 300 rad / s at 230 °C, 7% strain. Rheology was then monitored at 160 °C, 1.0 rad / s, 7% strain, for 60 min, followed by a frequency sweep from 0.1 to 300 rad / s at 160 °C, 7% strain on the same sample to monitor and assess recovery of the crosslinked network. The dynamic complex viscosity, n*, and tan delta were recorded for each frequency sweep. In ASTM D6204, frequency sweeps on unvulcanized rubber are conducted prior to a cure step. In this case, frequency sweeps were conducted after the initial crosslinking step at 160 °C to evaluate the reversibility of the crosslinking. Viscosity is reported in pascal-seconds (Pa»s).

[0029] Shore A Hardness was measured according to ASTM D2240 using a 10 second hold time.

[0030] Tensile properties were measured according to ASTM D1708 at 5 inches / minute using microtensile specimens cut from the compression molded plaques.DETAILED DESCRIPTION

[0031] The present disclosure provides a crosslinkable polymer composition. In an embodiment, the crosslinkable polymer composition includes an ethylene / propylene / non- conjugated polyene terpolymer, a free radical initiator, and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate).A. Ethylene / propylene / non-conjugated polyene terpolymer

[0032] The crosslinkable polymer composition includes an ethylene / propylene / non- conjugated polyene terpolymer. The terpolymer is an ethylene / propylene / non-conjugated polyene terpolymer composed of, in polymerized form, ethylene, propylene, and from 0.1 wt% to 10 wt% of a non-conjugated polyene termonomer, based on total weight of the terpolymer.

[0033] The ethylene / propylene / non-conjugated polyene terpolymer includes a nonconjugated polyene monomer as a termonomer in the terpolymer. A "non-conjugated polyene monomer," as used herein, is a monomer having two or more double bonds (typically, carboncarbon double bonds, or C=C) that are non-conjugated. A "conjugated double bond" system has two or more double bonds (typically, carbon-carbon double bonds or C-C), each double bond separated by one single bond. In other words, a monomer (or composition) with conjugated double bonds has double bonds alternating with single bonds, whereas non-conjugated bond systems have two or more double bonds separated by more than one single bond. A nonconjugated diene monomer is a monomer having two double bonds that are non-conjugated, that is the double bonds are separated by more than one single bond. A conjugated diene monomer is a monomer having two double bonds that are separated by one single bond (such as H2C=CH-CH=CH2, for example). Nonlimiting examples of conjugated diene include 1,3- butadiene and isoprene. The present ethylene / propylene / non-conjugated polyene terpolymer includes the non-conjugated polyene monomer to the exclusion of conjugated polyene, conjugated diene, and / or an aromatic compound.

[0034] The non-conjugated polyene termonomer includes C4-C40non-conjugated dienes. The non-conjugated diene can be an acyclic non-conjugated diene or a cyclic non-conjugated diene. Nonlimiting examples of acyclic non-conjugated dienes include straight chain acyclic nonconjugated dienes, such as 1,4-hexadiene and 1,5-heptadiene; and branched chain acyclic nonconjugated dienes, such as 5-methyl-l,4-hexadiene, 2-methyl-l,5-hexadiene, 6-methyl-l,5- heptadiene, 7-methyl-l,6-octadiene, 3,7-dimethyl-l,6-octadiene, 3,7-dimethyl-l,7-octadiene, 5,7-dimethyl-l,7-octadiene, and 1,9-deca-diene and mixed isomers of dihydromyrcene. Nonlimiting examples of cyclic non-conjugated dienes include monocyclic dienes such as 1,4- cyclohexadiene, 1,5-cyclooctadiene and 1,5-cyclododecadiene; multi-ring alicyclic fused and bridged ring dienes, such as tetrahydroindene and methyl tetrahydroindene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes such as 5-methylene-2-norbornene (MNB), 5- ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5- isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, and 5-cyclohexylidene-2- norbornene.

[0035] In an embodiment, the nonconjugated polyene is ENB.

[0036] In an embodiment, the ethylene / propylene / non-conjugated polyene terpolymer includes only one type of non-conjugated polyene. The single type of non-conjugated polyene is void of, or absent of, a heteroatom.

[0037] In an embodiment, the ethylene / propylene / non-conjugated polyene terpolymer is an ethylene / propylene / norbornene terpolymer. In a further embodiment, the terpolymer is an ethylene / propylene / ENB terpolymer. The term "EPDM," as used herein, is the ethylene / propylene / ENB terpolymer having only three monomers, and the ENB being the sole polyene in the terpolymer.

[0038] In an embodiment, the EPDM includes:(i) from 50 to 80 wt%, or from 50 to 75 wt%, or from 65 to 75 wt% polymerized ethylene,(ii) from 20 wt% to 49.9 wt%, or from 20 to 45 wt%, or from 25 to 35 wt% polymerized propylene,(iii) from 0.1 w% to 10 wt%, or from 0.2 wt% to 8.0 wt%, or from 0.3 wt% to 7.0 wt%, or from 0.5 wt% to 5.0 wt% polymerized ENB (wherein the aggregate amount of (i), (ii), (iii) is 100 wt% of the EPDM), and the EPDM has one, some, or all of the following properties:(iv) a Mooney viscosity from 10 MU to 90 MU, or from 15 MU to 80 MU, or from 15 MU to 25 MU, and / or(v) a density from 0.85 g / cc to 0.91 g / cc, or from 0.86 g / cc to 0.88 g / cc.B. Free radical initiator

[0039] The crosslinkable composition includes a free radical initiator. In an embodiment, the free radical initiator is an organic peroxide. Nonlimiting examples of suitable organic peroxide include bis(l,l-dimethylethyl) peroxide; bis(l,l-dimethylpropyl) peroxide; 2,5-dimethyl-2,5- bis(l,l-dimethylethylperoxy) hexane; 2,5-dimethyl-2,5-bis(l,l-dimethylethylperoxy) hexyne; 4,4-bis(l,l-dimethylethylperoxy) valeric acid; butyl ester; l,l-bis(l,l-dimethylethylperoxy)- 3,3,5-trimethylcyclohexane; benzoyl peroxide; tert-butyl peroxybenzoate; di-tert-amyl peroxide ("DTAP"); bis(a-t-butyl-peroxyisopropyl) benzene ("BIPB"); isopropylcumyl t-butyl peroxide; t- butylcumylperoxide; di-t-butyl peroxide; 2,5-bis(t-butylperoxy)-2,5-dimethylhexane; 2,5-bis(t- butylperoxy)-2,5-dimethylhexyne-3,l,l-bis(t-butylperoxy)-3,3,5- tri methylcyclohexane; isopropylcumyl cumylperoxide; butyl 4,4-di(tert-butylperoxy) valerate; di(isopropylcumyl) peroxide; dicumyl peroxide, and combinations thereof.

[0040] In an embodiment the free radical initiator is dicumyl peroxide.C. BiTEMPS methacrylate disulfide

[0041] The crosslinkable polymer composition includes 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide, interchangeably referred to as "BiTEMPS methacrylate disulfide," or "BiTEMPS methacrylate," or "BiTEMPS," or "BiT." BiTEMPS methacrylate disulfide has the Structure 1 below.Structure 1

[0042] In an embodiment, the crosslinkable polymer composition includes from 51 wt% to 99 wt%, or from 55 wt% to 97 wt%, or from 80 wt% to 96 wt%, or from 90 wt% to 95 wt% of the ethylene / propylene / non-conjugated polyene terpolymer (or EPDM for example); from 0.1 wt% to 1.5 wt%, or from 0.2 wt% to 1.0 wt%, or from 0.3 wt% to 1.0 wt% or from 0.5 wt% to 1.0 wt%, or from 0.5 wt% to 0.95 wt% free radical initiator that is an organic peroxide (such as dicumyl peroxide for example); and from 0.1 % to 10.0 wt%, or from 0.2 wt% to 8.0 wt%, or from 0.3 wt% to 7.0 wt% or from 0.5 wt% to 5.0 wt% BiTEMPS methacrylate disulfide. It is understood that the aggregate of the ethylene / propylene / non-conjugated polyene terpolymer, the free radical initiator, and the BiTEMPS methacrylate disulfide (and optional additives) amounts to 100 wt% of the crosslinkable polymer composition.

[0043] In an embodiment, the crosslinkable composition has a molar ratio of BiT to organic peroxide active oxygen from 0.5:1 to 3.0:1, or from 1.0:1 to 3.0:1, or from 1:1 to 2:1, or from 1:1 to 1.5:1, based on total weight of the crosslinkable composition.

[0044] In an embodiment, the crosslinkable composition has a molar ratio of BiT to ENB from 0.3:1 to 10:1, or from 0.4:1 to 5.0:1, or from 0.5:1 to 3.0:1, or from 0.5:1 to 2.5:1, or from 0.5:1 to 2.3:1, or from 1.0:1 to 2.5:1, where the ENB is in polymerized form in the ethylene / propylene / non-conjugated polyene terpolymer.D. Blend component

[0045] In an embodiment, the crosslinkable composition and / or the crosslinked composition includes a blend component. Nonlimiting examples of suitable blend component include ethylene vinyl acetate (EVA), polyolefins (e.g., polyethylene other than theethylene / propylene / non-conjugated polyene terpolymer), polymers (e.g., polystyrene, ABS, SBS and the like) and combinations thereof. Non-limiting examples of suitable polyolefins include polyethylene; polypropylene; polybutylene (e.g., polybutene-1); polypentene-1; polyhexene-1; polyoctene-1; polydecene-1; poly-3-methylbutene-l; poly-4-methylpentene-l; polyisoprene; polybutadiene; poly-1, 5-hexadiene; interpolymers derived from olefins, such as ethylene / a- olefin interpolymers; interpolymers derived from olefins and other polymers such as polyvinyl chloride, polystyrene, polyurethane, and the like; and mixtures thereof.

[0046] In an embodiment, the blend component is a polyolefin that is a homopolymer such as polyethylene, polypropylene, polybutylene, polypentene-1, poly-3-methylbutene-l, poly-4- methylpentene-1, polyisoprene, polybutadiene, poly-1, 5-hexadiene, polyhexene-1, polyoctene- 1 and polydecene-1.

[0047] Nonlimiting examples of suitable polyethylene as blend component (other than the ethylene / propylene / non-conjugated polyene terpolymer) include ultra low density polyethylene (ULDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), high molecular weight high density polyethylene (HMW-HDPE), ultra high molecular weight polyethylene (UHMW-PE) and combinations thereof. Nonlimiting examples of polypropylene as blend component include low density polypropylene (LDPP), high density polypropylene (HDPP), high-melt strength polypropylene (HMS-PP) and combination thereof. In an embodiment, the blend component is a high-melt-strength polypropylene (HMS-PP), a low density polyethylene (LDPE) or a combination thereof.

[0048] In an embodiment, the non-conjugated polyene is ethylidene-2-norbornene (ENB), and the article has a molar ratio of BiT to ENB from 0.3:1 to 10:1, or from 0.4:1 to 5.0:1, or from 0.5:1 to 3.0:1, or from 0.5:1 to 2.5:1, or from 0.5:1 to 2.3:1, or from 1.0:1 to 2.5:1, where the ENB is in polymerized form in the ethylene / propylene / non-conjugated polyene terpolymer.E. Additives

[0049] The crosslinkable composition may contain one or more optional additives. Nonlimiting examples of suitable additives include oil, filler, antioxidant, cure activator, crosslinkcoagent, blowing agent, blowing agent activators, plasticizers, processing aids, carbon black, colorants or pigments, stability control agents, nucleating agents, acid scavengers, ultraviolet (UV) stabilizers, flame retardants, lubricants, processing aids, extrusion aids, and combinations thereof. When present, the total amount of additive can be from greater than 0 to 80%, or from 0.001% to 70%, or from 0.01% to 60%, or from 0.1% to 50%, or from 0.1% to 40%, or from 0.1% to 20%, or from 0.1% to 10 %, or from 0.1% to 5% of the total weight of the crosslinkable composition.

[0050] In an embodiment, the crosslinkable composition includes an oil. Oils include, but are not limited to, petroleum oils, such as aromatic and naphthenic oils; polyalkylbenzene oils; organic acid monoesters, such as alkyl and alkoxyalkyl oleates and stearates; organic acid diesters, such as dialkyl, dialkoxyalkyl, and alkyl aryl phthalates, terephthalates, sebacates, adipates, and glutarates; glycol diesters, such as tri-, tetra-, and polyethylene glycol dialkanoates; trialkyl trimellitates; trialkyl, trialkoxyalkyl, alkyl diaryl, and triaryl phosphates; chlorinated paraffin oils; coumarone-indene resins; pine tars; vegetable oils, such as castor, tall, rapeseed, and soybean oils and esters and epoxidized derivatives thereof; and combinations thereof. In a further embodiment, the oil is selected from SUNPAR 2280, PARALUX 6001, HYDROBRITE 550, CALSOL 5550, and combinations thereof. The oil is present in an amount from 5 wt% to 40 wt%, or from 5 wt% to 20 wt%, or from 8 wt% to 10 wt% based on total weight of the crosslinkable composition.

[0051] In an embodiment, the crosslinkable composition includes a filler. Fillers include, but are not limited to, carbon black; silicates of aluminum, magnesium, calcium, sodium, potassium and mixtures thereof; carbonates of calcium, magnesium and mixtures thereof; oxides of silicon, calcium, zinc, iron, titanium, and aluminum; sulfates of calcium, barium, and lead; polyethylene glycol (PEG); sulfur; stearic acid; sulfonamide; alumina trihydrate; magnesium hydroxide; precipitated silica; fumed silica; natural fibers; synthetic fibers; clay, glass fibers, carbon fibers, and combinations thereof.

[0052] In an embodiment, the filler is present in an amount from 5 wt% to 70 wt%, or from 10 wt%, to 60 wt%, or from 20 wt% to 50 wt%, or from 25 wt% to 35 wt%, or from 25 wt% to 30 wt% based on total weight of the crosslinkable composition. In a further embodiment, the filleris calcium carbonate, and the calcium carbonate is present in an amount from 5 wt% to 70 wt%, or from 10 wt%, to 60 wt%, or from 20 wt% to 50 wt%, or from 25 wt% to 35 wt%, or from 25 wt% to 30 wt% based on total weight of the crosslinkable composition.

[0053] In an embodiment, the crosslinkable composition includes an antioxidant. Nonlimiting examples of suitable antioxidants include aromatic or hindered amines such as alkyl diphenylamines, phenyl-a-naphthylamine, alkyl or aralkyl substituted phenyl-a-naphthylamine, alkylated p-phenylene diamines, tetramethyl-diaminodiphenylamine and the like; phenols such as 2,6-di-t-butyl-4-methylphenol; l,3,5-trimethyl-2,4,6-tris(3,5,-di-t-butyl-4,- hydroxybenzyljbenzene; tetrakis[(methylene(3,5 -di-t-butyl-4- hydroxyhydrocinnamate)]methane (e.g., IRGANOX™ 1010, from Ciba Geigy, NewYork); acryloyl modified phenols; octadecyl-3,5- di-t-butyl-4-hydroxycinnamate (e.g., IRGANOX™ 1076, commercially available from Ciba Geigy); phosphites and phosphonites; hydroxylamines; benzofuranone derivatives; quinolines, and combinations thereof. Where used, the amount of the antioxidant in the crosslinkable composition is from greater than 0 wt% to 5 wt%, or from 0.0001 to 2.5 wt%, or from 0.001 to 1 wt%, or from 0.01 to 0.5 wt% of the total weight of the crosslinkable composition.

[0054] In an embodiment, the crosslinkable composition includes a cure activator. Where used, the amount of cure activator is from greater than 0 wt% to 5 wt%, or from 0.0001 to 2.5 wt%, or from 0.001 to 2.0 wt%, or from 0.01 to 1.5 wt% of the total weight of the crosslinkable composition. In a further embodiment, the cure activator is zinc oxide and is present from greater than 0 wt% to 5 wt%, or from 0.0001 to 2.5 wt%, or from 0.001 to 2.0 wt%, or from 0.01 to 1.5 wt% of the total weight of the crosslinkable composition.

[0055] In an embodiment, the crosslinkable composition includes a crosslink coagent. Where used, the amount of crosslink coagent is from greater than 0 wt% to 5 wt%, or from 0.0001 to 2.5 wt%, or from 0.001 to 2.0 wt%, or from 0.01 to 1.5 wt% of the total weight of the crosslinkable composition. In a further embodiment, the crosslink coagent is trimethylolpropane methacrylate and is present from greater than 0 wt% to 5 wt%, or from 0.0001 to 2.5 wt%, or from 0.001 to 2.0 wt%, or from 0.01 to 1.5 wt% of the total weight of the crosslinkable composition.

[0056] In an embodiment, the crosslinkable composition includes(A) from 51 wt% to 99 wt%, or from 55 wt% to 97 wt%, or from 80 wt% to 96 wt%, or from 90 wt% to 95 wt% of the ethylene / propylene / non-conjugated polyene terpolymer (or EPDM for example);(B) from 0.1 wt% to 1.5 wt%, or from 0.2 wt% to 1.0 wt%, or from 0.3 wt% to 1.0 wt% or from 0.5 wt% to 1.0 wt% free radical initiator that is an organic peroxide (such as dicumyl peroxide for example); and(C) from 0.5 % to 10.0 wt%, or from 0.5 wt% to 5.0 wt%, or from 2.0 wt% to 5.0 wt% BiTEMPS methacrylate disulfide.

[0057] In an embodiment, the crosslinkable composition includes(A) from 51 wt% to 98 wt%, or from 52 wt% to 65 wt%, or from 53 wt% to 60 wt%, of the ethylene / propylene / non-conjugated polyene terpolymer (or EPDM for example);(B) from 0.1 wt% to 1.5 wt%, or from 0.2 wt% to 1.0 wt%, or from 0.3 wt% to 1.0 wt% or from 0.5 wt% to 0.7 wt% free radical initiator that is an organic peroxide (such as dicumyl peroxide for example);(C) from 0.5 wt% to 5.0 wt%, or from 0.7 wt% to 4.8 wt%, or from 1.0 wt% to 4.5 wt%, or from 1.5 wt% to 4.0, or from 1.5 wt% to 3.5 wt% BiTEMPS methacrylate disulfide;(D) from 5 wt% to 40 wt%, or from 5 wt% to 15 wt%, or from 5 wt% to 10 wt% oil; and / or(E) from 5 wt% to 70 wt%, or from 20 wt% to 40 wt%, or from 25 wt% to 35 wt% filler (such as calcium carbonate); and / or(F) from 0.01 wt% to 1.0 wt%, or from 0.1 wt% to 0.5 wt% antioxidant; and / or(G) from 0.01 wt% to 5 wt%, or from 0.1 wt% to 1.5 wt% cure activator; and / or(H) from 0 wt% to 5 wt%, or from 0.1 wt% to 1.5 wt% crosslink coagent.F. Article

[0058] The present disclosure provides an article. The crosslinkable polymer composition is melt blended at a temperature from 80°C to 250°C, or from 120°C to 200°C, or from 140°C to 200°C, or from 150°C to 190°C to trigger the crosslinking reaction and be shaped into, or otherwise be formed into, an article composed of, or otherwise made from, the crosslinked composition. When the coagent is present in the crosslinkable composition, the coagentbecomes part of the crosslinked network. When the cure activator is present in the crosslinkable composition, the cure activator remains in the crosslinked composition.

[0059] The free radical is consumed to form the crosslinked composition. The article includes the crosslinked composition composed of ethylene / propylene / non-conjugated polyene terpolymer and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate). The crosslinked composition contains sulfide linkages formed from the BiTEMPS methacrylate by way of the crosslinking reaction, the sulfide linkages depicted in the Structure 2 below.Structure 2

[0060] The term (and structure) "P" in Structure 2 above refers to the ethylene / propylene / non-conjugated polyene polymer chain. The BiT may bond to any part of the ethylene / propylene / non-conjugated polyene polymer chain. Further, the synthesis of BiTEMPS methacrylate results in the formation of polysulfide derivatives of BiTEMPS such as disulfides, trisulfides and tetrasulfides as additional products. It is understood that these polysulfide derivatives may be present in the crosslinked composition.

[0061] Nonlimiting examples of articles that can be formed from the crosslinked composition include automotive parts (automotive weather seals, automotive belts, automotive hoses), belts, building materials, cables, computer parts, extruded profiles, foams, footwear, gaskets, hoses, membranes, molded goods, roofing sheets, tires, weather stripping, and wire components.

[0062] The ethylene / propylene / non-conjugated polyene terpolymer of the crosslinked composition can be any ethylene / propylene / non-conjugated polyene terpolymer previously disclosed herein.

[0063] In an embodiment, the article includes a crosslinked composition composed of(A) from 51 wt% to 99 wt%, or from 55 wt% to 97 wt%, or from 80 wt% to 96 wt%, or from 90 wt% to 95 wt% ethylene / propylene / ENB terpolymer with(i) from 50 wt% to 80 wt%, or from 50 wt% to 75 wt%, or from 65 to 75 wt% polymerized ethylene(ii) from 20 wt% to 49.9 wt%, or from 20 wt% to 45 wt%, or from 25 wt% to 35 wt% polymerized propylene,(iii) from 0.1 wt% to 10 wt%, or from 0.2 wt% to 8.0 wt%, or from 0.3 wt% to 7.0 wt%, or from 0.5 wt% to 5.0 wt% polymerized ENB (wherein the aggregate amount of (i), (ii), (iii) is 100 wt% of the EPDM), and(B) from 0.5 wt% to 10.0 wt%, or from 0.5 wt% to 5.0 wt%, or from 2.0 wt% to 5.0 wt%, BiTEMPS methacrylate, wherein (A) and (B) amount to 100 wt% of the crosslinked composition.

[0064] In an embodiment, the article includes a crosslinked composition is composed of(A) from 51 wt% to 98 wt%, or from 52 wt% to 65 wt%, or from 53 wt% to 60 wt%, ethylene / propylene / ENB terpolymer with(i) from 50 wt% to 80 wt%, or from 50 wt% to 75 wt%, or from 65 to 75 wt% polymerized ethylene(ii) from 20 wt% to 49.9 wt%, or from 20 wt% to 45 wt%, or from 25 wt% to 35 wt% polymerized propylene,(iii) from 0.1 wt% to 10 wt%, or from 0.2 wt% to 8.0 wt%, or from 0.3 wt% to 7.0 wt%, or from 0.5 wt% to 5.0 wt% polymerized ENB (wherein the aggregate amount of (i), (ii), (iii) is 100 wt% of the EPDM), and(B) from 0.5 wt% to 5.0 wt%, or from 0.7 wt% to 4.8 wt%, or from 1.0 wt% to 4.5 wt%, or from 1.5 wt% to 4.0 wt%, or from 1.5 wt% to 3.5 wt% BiTEMPS methacrylate disulfide;(C) 0 wt%, or from 5 wt% to 40 wt%, or from 5 wt% to 15 wt%, or from 5 wt% to 10 wt% oil; and / or(D) 0 wt%, or from 5 wt% to 70 wt%, or from 20 wt% to 40 wt%, or from 25 wt% to 35 wt% filler (such as calcium carbonate); and / or(E) 0 wt%, or from 0.01 wt% to 1.0 wt%, or from 0.1 wt% to 0.5 wt% antioxidant; and / or(F) 0 wt%, or from 0.01 wt% to 5 wt%, or from 0.1 wt% to 1.5 wt% cure activator; and / or(G) 0 wt%, or from 0.01 wt% to 5 wt%, or from 0.1 wt% to 1.5 wt% crosslink coagent.

[0065] BiTEMPS methacrylate is a "dynamic crosslinker." The dynamic crosslinker BiTEMPS methacrylate enables formation of a crosslinked network with the ethylene / propylene / non- conjugated polyene terpolymer by way of disulfide linkages between the chains of the ethylene / propylene / non-conjugated polyene terpolymer (in the presence of the free radical initiator) to form the crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition. The crosslinking is dynamic because the disulfide linkages may be broken, allowing for chain mobility and exchange when the crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition is subjected to a "reprocessing temperature," the reprocessing temperature being a temperature from 160 °C to 230 °C, or from 160 °C to 200 °C. At the reprocessing temperature, the disulfide linkages in the crosslinked ethylene / propylene / non- conjugated polyene terpolymer composition are broken, forming a re-processable ethylene / propylene / non-conjugated polyene terpolymer composition. Cooling the reprocessable ethylene / propylene / non-conjugated polyene terpolymer below the reprocessing temperature forms a re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition.

[0066] The dynamic crosslinker BiTEMPS methacrylate enables a cyclic "reprocessing" for fabrication of new polymeric articles. When the crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition is heated to the reprocessing temperature, the disulfide linkages break, or otherwise cleave, enabling the previously-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition to flow at the reprocessing temperature, forming "a re-processable ethylene / propylene / non-conjugated polyene terpolymer composition." Heating to the reprocessing temperature enables link breaking and polymer chain flow, allowing the ethylene / propylene / non-conjugated polyene terpolymer to be reshaped readily. At the reprocessing temperature, the re-processable ethylene / propylene / non-conjugated polyene terpolymer composition is no longer crosslinked, but rather is flowable, enabling shaping and / or fabrication of the now flowable re-processable ethylene / propylene / non-conjugated polyene terpolymer composition (with BiTEMPS methacrylate) into a new pre-form or article.Yl

[0067] In an embodiment, at the reprocessing temperature, an additive is added to the reprocessable ethylene / propylene / non-conjugated polyene terpolymer composition (which is no longer crosslinked, but rather is flowable) to form a new composition. Nonlimiting examples of suitable additives include oil, filler, antioxidant, cure activator, crosslink coagent, blowing agent, blowing agent activators, plasticizers, processing aids, carbon black, colorants or pigments, stability control agents, nucleating agents, acid scavengers, ultraviolet (UV) stabilizers, flame retardants, lubricants, processing aids, extrusion aids, and combinations thereof. In a further embodiment, the additive is a component selected from oil, filler, antioxidant, cure activator, crosslink agent, and combinations thereof.

[0068] Upon cooling to below the "reprocessing temperature," the disulfide linkages form again, the network is re-established, and the re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition is formed in the new article configuration with a return to the high viscosity (no flow at room temperature) and resistance to mechanical deformation indicative of the crosslinked network. When the newly-formed article of the re-processable ethylene / propylene / non-conjugated polyene terpolymer composition is cooled below the reprocessing temperature, the disulfide linkages in the re-processable ethylene / propylene / non- conjugated polyene terpolymer composition are re-established, and the ethylene / propylene / non-conjugated polyene terpolymer (with BiTEMPS methacrylate) becomes a re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition in the shape of the newly-fabricated article. Below the reprocessing temperature, the network disulfide linkages are stable, and the re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition exhibits the high viscosity and resistance to mechanical deformation indicative of a crosslinked network. This cycle of crosslink / re-process / re-crosslink and fabrication into a new article can be repeated.

[0069] Bounded by no particular theory, the number of "reprocessing" cycles that are possible with the present crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition (before competitive thermal and oxidative permanent crosslinking occurs and prevents further reprocessing), can be determined by calculating the ratio of the melt viscosity of the crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition beforeand after a reprocessing cycle. For the crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition to be re-processable, the ratio of the melt viscosity after reprocessing to the melt viscosity before reprocessing is from 0.1 to 5, or from 0.7 to 3 or from 0.8 to 1.3.

[0070] Other metrics for monitoring the number of "reprocessing" cycles that are possible with the BiTEMPS methacrylate dynamic crosslinker before competitive oxidative permanent crosslinking occurs include visual observation. A plaque that is mechanically deformed and / or cut is heated to the reprocessing temperature and then cooled, and is visually inspected to determine whether the mechanically deformed and / or cut plaque heals to form a stable plaque. This metric of re-processability is noted in Table 4-6 below and demonstrated in FIG. 1 - FIG 7.G. Process

[0071] The present disclosure provides a process. In an embodiment, the process includes heating a first article to a reprocessing temperature. The first article is made from, or otherwise composed of, a crosslinked composition. The crosslinked composition includes the ethylene / propylene / non-conjugated polyene terpolymer (or the EPDM for example), and linkages having the Structure (2) (formed from 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS methacrylate)). The process includes forming, at the reprocessing temperature, the first article into a re-processable ethylene / propylene / non-conjugated polyene terpolymer composition (or re-processable EPDM). The process includes shaping, at the reprocessing temperature, the re-processable ethylene / propylene / non-conjugated polyene terpolymer composition (or re-processable EPDM) into a re-processed pre-form. The process includes cooling the re-processed pre-form to below the reprocessing temperature and forming a second article composed of a re-crosslinked ethylene / propylene / non-conjugated polyene terpolymer composition (or re-crosslinked EPDM) composed of (i) the ethylene / propylene / non- conjugated polyene terpolymer (or EPDM) and (ii) the BiTEMPS methacrylate.

[0072] The second article can be the same as, or different than, the first article.

[0073] In an embodiment, the shaping step is a procedure selected from injection molding, extrusion, extrusion molding, thermoforming, slush molding, over molding, insert molding, blow molding, cast molding, tentering, compression molding, and combinations thereof.

[0074] In an embodiment, the process includes heating a first article to a reprocessing temperature, the first article composed of a crosslinked composition comprising (i) an ethylene / propylene / non-conjugated polyene terpolymer; and (ii) linkages of Structure 2(Structure 2); forming, at the reprocessing temperature, the first article into a re-processable ethylene / propylene / non-conjugated polyene terpolymer composition; adding an additive to the re-processable ethylene / propylene / non-conjugated polyene terpolymer composition; shaping, at the reprocessing temperature, the re-processable ethylene / propylene / non- conjugated polyene terpolymer composition and the additive into a re-processed pre-form; cooling the re-processed pre-form to below the reprocessing temperature; and forming a second article composed of a re-crosslinked ethylene / propylene / non- conjugated polyene terpolymer composition composed of (i) the ethylene / propylene / non- conjugated polyene terpolymer, with (ii) linkages having the Structure 2, and the additive. Nonlimiting examples of suitable additives include oil, filler, antioxidant, cure activator, crosslink coagent, blowing agent, blowing agent activators, plasticizers, processing aids, carbon black, colorants or pigments, stability control agents, nucleating agents, acid scavengers, ultraviolet (UV) stabilizers, flame retardants, lubricants, processing aids, extrusion aids, and combinations thereof. In a further embodiment, the additive is a component selected from oil, filler, antioxidant, cure activator, crosslink agent, and combinations thereof.

[0075] In an embodiment, the first article has a first tensile strength and the second article has a second tensile strength. The second tensile strength (for the second article) is within 50%, or within 40%, of the value of the first tensile strength (in MPa) for the first article. In a further embodiment, the tensile strength of the second article is greater than or equal to 5.0 MPa, orfrom 5.0 MPa to 10.0 MPa and the second tensile strength is within 50% of the value of the first tensile strength (in MPa).

[0076] Nonlimiting examples of suitable second articles for the present crosslinked / re- crosslinked ethylene / propylene / non-conjugated polyene terpolymer (with BiTEMPS methacrylate) composition include automotive parts (automotive weather seals, automotive belts, automotive hoses), belts, building materials, cables, computer parts, extruded profiles, foams, footwear, gaskets, hoses, tubing, membranes, molded goods, roofing sheets, tires, weather stripping, wire components, elastic film, elastic fiber, soft touch good (such as tooth brush handles and appliance handles), footwear (including shoe soles and shoe liners), auto interior parts and profiles, foam articles (both open cell foam and closed cell foam), impact modifiers for other thermoplastic polymers (such as high density polyethylene, isotactic polypropylene, or other olefin polymers), flooring, and combinations thereof.

[0077] Applicant discovered the present crosslinked EPDM (with BiT) is capable of undergoing reversible crosslinking at reprocessing temperatures. This is achieved by forming an article composed of a crosslinked composition of ethylene / propylene / non-conjugated polyene terpolymer, peroxide, and BITEMPS methacrylate. The BiTEMPS methacrylate is used as a crosslinking aid together with peroxide to create a crosslinked EPDM network with high- temperature mechanical properties that can still be melt re-processed. The BiTEMPS methacrylate enables C-C bonds to be formed between the BiTEMPS methacrylate and EPDM chain via the acrylate groups. This bond formation is mediated by certain peroxides that generate free radicals. The crosslinked composition is crosslinked at application use temperatures but can be melt reprocessed at typical extruded profile processing temperatures (~160 - 250 °C). The S- S bond in the BiTEMPS structure can dissociate to N-S radicals at elevated temperatures and reassociate at lower temperatures under conditions of use, enabling melt re-processing of the crosslinked EPDM. This dissociation / reassociation cycle can occur multiple times. This "reversible crosslinking" enables re-processing and re-use ( / .e., mechanical recycling) of crosslinked EPDM. The BiTEMPS-modified EPDM can be re-processed at high temperature and be reformed, or otherwise re-shaped, into an article. The reprocessing of a BiTEMPS crosslinked EPDM offers asolution for reduction and re-use of post-industrial scrap and end-of-life management of collected parts composed of EPDM.

[0078] By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following examples.

[0079] 1. Materials

[0080] Materials used in the comparative samples (CS) and inventive examples (IE) are provided in Table 1 below.Table 11. Synthesis of BiTEMPS methacrylate

[0081] Synthesis of cross-linker bis(2,2,6,6-tetramethyl-4-piperidyl methacrylate) disulfide (BiTEMPS methacrylate) was prepared via modification of the literature procedure (Macromolecules 2020, 53, 8367-8373) to make it practical for scale-up synthesis.

[0082] In a nitrogen-filled glove box, 2,2,6,6-tetramethyl-4-piperidyl methacrylate (TMPM, 80.00 g, 355 mmol, 1 equiv) was dissolved in pre-dried, degassed THF (440 mL). Triethylamine (247 mL, 1775 mmol, 5 equiv) was added, and the solution was taken to a fume hood and cooled to -35 °C (acetone / dry ice) while stirring, and then sulfur monochloride (14.2 mL, 177 mmol, 0.5 equiv) mixed with THF (40 mL) was added to the solution via syringe pump over 15 min. A yellow suspension formed. The suspension was allowed to warm to room temperature and stirred for 30 minutes at ambient temperature. The mixture was then poured into de-ionized (DI) water (3 L) and stirred at room temperature overnight, then poured into a separatory funnel, mixed with brine (200 mL), and extracted with diethyl ether (1 L). The organic phase was saved in a bottle and the aqueous phase was extracted again with diethyl ether (1 L). The combined organic phase was dried over MgSOzi, and filtered. Solvent was removed under vacuum to give an oil, which was then mixed with methanol (500 mL), cooled in the freezer (-20 °C) and filtered later. The resulting white solid was dried under vacuum overnight (52.93 g, 55%). BiTEMPS methacrylate is shown as Structure 1 below.Structure 1

[0083] The synthesis of BiTEMPS methacrylate results in the formation of polysulfide derivatives of BiTEMPS such as disulfides, trisulfides and tetrasulfides as additional products. It is understood that these polysulfide derivatives may be present in the crosslinked composition.2. Preparation of crosslinked compositions

[0084] Compounds were prepared by batch mixing in an RSI RS5000 RHEOMIX 600 batch mixer (commonly referred to as a Haake Batch Mixer available from PolyLab) with CAM blades. For compounds with oil, the polymer or polymer compound pellets and oil were placed in a glass jar, mixed by hand, and allowed to sit overnight at ambient conditions to allow the oil to imbibeinto the EPDM polymer. For batch mixing, the polymer or polymer / oil blend was added to the mixer and the mixing speed set to 20 rpm. Once the polymer had melted, the CaCOs and Agerite Resin D were added and allowed to mix in for approximately 2 minutes. Then, the BiTEMPS, peroxide, SR517 coagent, and ZnO were added to the mixer. The mixing speed was increased to 50 rpm and the batch mixed for 5 minutes. Compounds were mixed at 100 °C to allow mixing of the components without decomposition of the peroxide. The compound was then removed from the Haake mixer and compressed into a patty using the cold platens (T ~ 20 °C) of a Carver hydraulic press at 20,000 psi for four minutes.

[0085] The rheology and curing of the compounds were evaluated using a Rubber Process Analyzer (RPA). The cure profile of the samples was evaluated using a time sweep at 160 °C, 7% angle, 1 rad / s for 60 min, followed by a frequency sweep at 160 °C, 7% strain, 0.1 - 300 rad / s. To assess the reprocessability and viscosity change of the samples, frequency sweeps at 190 °C and 230 °C (7% strain, 0.1 - 300 rad / s) were then conducted, followed by a time sweep at 160 °C, 1 rad / s, 7% angle for 60 min, and a frequency sweep at 160 °C (7% strain, 0.1 - 300 rad / s).

[0086] The compounds were compression molded to form samples for mechanical property testing. Plaques 75 mm x 75 mm x 1.5 mm and 1 inch diameter x 0.5 inch thick buttons were compression molded on Carver hydraulic press with 30,000 Ibf at 180 °C for 15 minutes. For samples with peroxide (CS-A, CS-B, CS-D, CS-E, IE-1, IE-2, IE-3), this initiated peroxide decomposition and crosslinking of the compounds, thereby forming crosslinked compositions. For samples without peroxide, (CS-C and IE-4), compression molding into plaques was performed in the same manner (CS-A, CS-B, CS-C, CS-D, CS-E, IE-1, IE-2, IE-3, and IE-4 collectively referred to as "test samples").

[0087] For composition IE-4, a reversibly crosslinked composition was used. As described above, crosslinkable composition IE-1 was prepared on the Haake mixer then crosslinked by compression molding. The sample was cut into pieces and imbibed with oil as described above. The same mixing procedure as described above for the crosslinkable composition was used, except the mixer temperature was 180 °C because the polymer component in IE-4 is IE-1 (NORDEL 3722 crosslinked with BiTEMPS).

[0088] Tensile strength, hardness, and compression set properties of the test samples were measured.3. Reversible crosslinked compositions (remold)

[0089] Following tensile strength and hardness testing of the test samples, test samples were chopped into pieces (~1 cm x 1 cm) and remolded into 75 mm x 75 mm x 1.5 mm plaques on Carver hydraulic press with 30,000 Ibf at 180 °C for 15 minutes to form remolded test samples. To assess the reprocessability for the remolded test samples, the remolded samples were assessed visually and, where stable, intact plaques could be remolded, tensile testing was conducted on the remolded samples.

[0090] Table 2 below provides the formulations for the crosslinkable compositions. Table 3 below provides the formulation using a reversibly crosslinked composition. Table 4 below provides the RPA data for the compositions after Haake blending. Table 5 below provides physical properties of the compositions after the first compression molding. Table 6 below provides physical properties of the compositions after remolding.

[0091] Table 2: Formulations for the crosslinkable compositions*Molecular weight of BiT = 512.8 g / mol , Molecular weight of DCP = 270.4 g / mol. Decomposition of DCP results in two active oxygen radicals.

[0092] Table 3: Formulation with a reversibly crosslinked composition

[0093] Table 4: RPA Data for Compositions after Haake Blending

[0094] Table 5: Measured Properties of Compositions after First Molding

[0095] Table 6: Measured Properties of Compositions after Second Molding‘Sample could not be remolded. Cut pieces did not fuse back together during remolding.

[0096] In Table 4, the RPA results are summarized and indicate whether a material was crosslinked based on RPA S' value, and whether the crosslinked compositions were reprocessable based on VRR (i.e., viscosity ratio, VRR = RPA n*@ 160 °C, 0.1 rad / s / RPA n* @ 230 °C, 0.1 rad / s). A high RPA S' value was an indication that the composition during initial curing step can reach a crosslinked state. The observation of a high S' value in Table 4 was also found to be consistent with the measured physical properties of the crosslinked materials, including relatively low compression set at 100°C. CS-C which contained no peroxide and was not crosslinked had a low S' value and melted during compression set testing at 100 °C as this temperature was higher than the melting temperature of the NORDEL 3722 EPDM. All other samples were crosslinked, either permanently or reversibly.

[0097] A high VRR (greater than 1.6) is needed to reprocess the crosslinked materials. This is because the viscosity of an irreversibly crosslinked material (a composition with DCP and no BiTEMPS) at a processing temperature such as 230°C, typically does not have enough viscosity drop to become reprocessable. CS-A and CS-B include peroxide, but no BiTEMPS methacrylate. The low VRR values for these samples indicate they are not reprocessable. CS-C has a high VRR value, indicating it is reprocessable. However, as indicated above CS-C has no crosslinking and thus has poor high temperature mechanical properties. CS-D and CS-E include peroxide and BiTEMPS methacrylate, but both have low VRR values indicating they are not reprocessable, likely due to a higher degree of permanent crosslinks formed than reversible disulfide linkages. In CS- D, the ratio of BiTEMPS methacylate to peroxide was low, resulting in more permanent crosslinks than reversible disulfide linkages between EPDM chains. In CS-E, the ENB content of the EPDM was high, resulting in a low ratio of BiTEMPS methacrylate to ENB. This also resulted in an irreverisibly crosslinked network in CS-E. However, the inventive examples IE1-IE4 each demonstrated a significant drop in viscosity at 230°C (i.e., VRR > 1.6) due to cleavage of the disulfide linkages, and thus IE1-IE4 are reprocessable.

[0098] As shown in Table 5 and Table 6, only the inventive examples IE-2, IE-3, and IE-4 provide a combination of high temperature compression set performance with reprocessability into articles that retain the physical properties of the originally molded articles. CS-A is highly crosslinked with a conventional peroxide and coagent forming no reversible crosslink points.T1While CS-A (base formulation) has excellent higher temperature compression set performance, CS-A cannot be reprocessed as demonstrated by the image in FIG. 1 that shows the material breaks into pieces when attempting to remold after CS-A has been crosslinked.

[0099] CS-B (low peroxide, 1.4 wt% peroxide) has a lower crosslink density, so CS-B could be partially remolded. However, the CS-B sample could not be readily reshaped into the full dimensions of the mold. Also, the tensile properties for CS-B were significantly lower after remolding, suggesting incomplete / ineffective reformation of the broken network.

[0100] CS-C contains no peroxide and is not crosslinked ( / .e., CS-C is thermoplastic). Therefore CS-C can be readily reprocessed but has poor high temperature mechanical properties when tested above the melting point of the polymer.

[0101] IE-2, IE-3, and IE-4 each show a balance of high temperature properties, reprocessability, and retention of physical properties after remolding. IE-1 demonstrates that peroxide-mediated crosslinking of EPDM with BiTEMPS methacrylate can be done in the presence of EPDM only. IE-2 and IE-3 demonstrate that peroxide-mediated crosslinking of EPDM can be done in the presence of other compound ingredients such as oils, fillers, and other crosslinking coagents. IE-4 demonstrates that a composition of EPDM crosslinked with BiTEMPS methacrylate can be reprocessed with additional compound ingredients such as oils and fillers and still reform into a reprocessable crosslinked composition.

[0102] CS-D has a BiT / peroxide ratio of 0.4 and is not reprocessable. For CS-D, Table 5 shows the first tensile strength is 10.6 MPa and Table 6 shows the second tensile strength is 4.4 MPa. For CS-D, the second tensile strength (4.4 MPa) is 58% of the value of the first tensile strength (10.6 MPa) placing CS-D outside of 50% of the value of the first tensile strength; making CS-D not reprocessable. CS-D demonstrates that the BiT / peroxide ratio must be from 0.5 to 3 for reprocessable. In CS-D the BiT / peroxide ratio is too low (0.4) and therefore, too many permanent crosslinks are formed compared to the number of reversible crosslinks.

[0103] In CS-E, the molar ratio of BiT to ENB is 0.2 and CS-E is permanently crosslinked, CS-E cannot reversibly crosslink. CS-E shows that the BiT / ENB molar ratio must be from 0.3 to 10. In CS-E the BiT / ENB ratio is too low (0.2) and therefore too many permanent crosslinks are formed compared to the number of reversible crosslinks.

[0104] IE-2 shows reprocessability and re-crosslinkability. IE-2 shows a large decrease in viscosity upon heating with VRR of 1.7. For IE-2, Table 5 shows the first tensile strength (first mold) is 7.0 MPa and Table 6 shows the second tensile strength (second mold) is 6.1 MPa. For IE-2, the second tensile strength (6.1 MPa) is 14% of the value of the first tensile strength (6.1 MPa) placing IE-2 within 50% of the value of the first tensile strength; making IE-2 re- crosslinkable.

[0105] IE-3 shows reprocessability and re-crosslinkability. IE-3 processability is improved when the crosslinking coagent (SARET SR517) is not used. IE-3 has a VRR of 3.1. For IE-3, Table 5 shows the first tensile strength (first mold) is 7.1 MPa and Table 6 shows the second tensile strength (second mold) is 7.2 MPa. For IE-3, the second tensile strength (7.2 MPa) is 0% of the value of the first tensile strength (7.1 MPa) placing IE-3 within 50% of the value of the first tensile strength; making IE-3 re-crosslinkable.

[0106] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combination of elements of different embodiments as come within the scope of the following claims.

Claims

CLAIMS1. A crosslinkable polymer composition comprising: an ethylene / propylene / non-conjugated polyene terpolymer; a free radical initiator; and2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS).

2. The crosslinkable polymer composition of claim 1 wherein the ethylene / propylene / non- conjugated polyene terpolymer comprises from 0.1 wt% to 10 wt% of a non-conjugated polyene selected from the group consisting of 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,5- cyclododecadiene, tetrahydroindene, methyl tetrahydroindene, 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5- isopropylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene, and 5-cyclohexylidene-2- norbornene.

3. The crosslinkable composition of any of claims 1-2 comprising:(A) from 51 wt% to 99.4 wt% of the ethylene / propylene / non-conjugated polyene terpolymer;(B) from 0.1 wt% to 1.5 wt% of the free radical initiator that is an organic peroxide; and(C) from 0.5 wt% to 10.0 wt% of the BiTEMPS.

4. The crosslinkable composition of any of Claims 1-3 comprising a component selected from the group consisting of an oil, a filler, an antioxidant, a cure activator, a crosslink coagent, and combinations thereof.

5. The crosslinkable composition of any of Claims 1-4 comprising:(A) from 51 wt% to 98 wt% of the ethylene / propylene / non-conjugated polyene terpolymer;(B) from 0.1 wt% to 1.5 wt% of an organic peroxide;(C) from 0.5 wt% to 5.0 wt% of the BiTEMPS;(D) from 5 wt% to 40 wt% of an oil;(E) from 5 wt% to 70 wt% of a filler;(F) from 0.01 wt% to 1.0 wt% of an antioxidant;(G) from 0.01 wt% to 5 wt% of a cure activator; and(H) from 0 wt% to 5 wt% of a crosslink coagent.

6. The crosslinkable composition of any of claims 3-5 having a molar ratio of BiTEMPS to organic peroxide oxygen radicals from 0.5:1 to 3.0:1.

7. An article comprising: a crosslinked composition comprising an ethylene / propylene / non-conjugated polyene terpolymer; and 2,2,6,6-tetramethyl-4-piperidyl methacrylate disulfide (BiTEMPS).

8. The article of claim 7 wherein the ethylene / propylene / non-conjugated polyene terpolymer comprises from 0.1 wt% to 10 wt% of a non-conjugated polyene selected from the group consisting of 1,4-cyclohexadiene, 1,5-cyclooctadiene, 1,5-cyclododecadiene, tetrahydroindene, methyl tetrahydroindene, 5-methylene-2-norbornene (MNB), 5-ethylidene- 2-norbornene (ENB), 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-isopropylidene-2- norbornene, 5-(4-cyclopentenyl)-2-norbornene, and 5-cyclohexylidene-2-norbornene.

9. The article of any of claims 7-8 wherein the crosslinked composition comprises linkages of Structure 2Structure 210. The article of any of claims 7-9 wherein the non-conjugated polyene is ethylidene-2- norbornene (ENB), and the crosslinked composition has molar ratio of BiTEMPS to ENB from 0.3:1 to 10:1.

11. The article of any of claim 7-10 wherein the crosslinked composition comprises from 51 wt% to 99.5 wt% of the ethylene / propylene / non-conjugated polyene terpolymer; and from 0.5 wt% to 10.0 wt% of the BiTEMPS.

12. The article of claim 11 wherein the crosslinked composition comprises from 5 wt% to 40 wt% of an oil; and from 5 wt% to 70 wt% of a filler.

13. The article of any of claims 7-12 wherein the crosslinked composition has an RPA S' value after 60 minutes at 160 °C from 1.0 to 2.0.

14. A process comprising: heating a first article to a reprocessing temperature, the first article composed of a crosslinked composition comprising(i) an ethylene / propylene / non-conjugated polyene terpolymer; and(ii) linkages of Structure 2(Structure 2); forming, at the reprocessing temperature, the first article into a re-processable ethylene / propylene / non-conjugated polyene terpolymer composition;shaping, at the reprocessing temperature, the re-processable ethylene / propylene / non- conjugated polyene terpolymer composition into a re-processed pre-form; cooling the re-processed pre-form to below the reprocessing temperature; and forming a second article composed of a re-crosslinked ethylene / propylene / non- conjugated polyene terpolymer composition composed of (i) the ethylene / propylene / non- conjugated polyene terpolymer and (ii) linkages having the Structure 2.

15. The process of claim 14 comprising adding an additive to the re-processable ethylene / propylene / non-conjugated polyene terpolymer composition; shaping, at the reprocessing temperature, the re-processable ethylene / propylene / non- conjugated polyene terpolymer composition and the additive into a re-processed pre-form; cooling the re-processed pre-form to below the reprocessing temperature; and forming a second article composed of a re-crosslinked ethylene / propylene / non- conjugated polyene terpolymer composition composed of (i) the ethylene / propylene / non- conjugated polyene terpolymer, with (ii) linkages having the Structure 2, and the additive.

16. The process of any of claims 14-15 wherein the first article has a first tensile strength and the second article has a second tensile strength and the second tensile strength is within 50% of the value of the first tensile strength.

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